From: jobst.brandt@stanfordalumni.org
Subject: Re: Revolutionary New Bicycle
Newsgroups: alt.religion.unification,alt.inventors,rec.bicycles.misc,
	rec.bicycles.racing,rec.bicycles.soc
Message-ID: <DSwd9.18194$Ik.456790@typhoon.sonic.net>
Date: Wed, 04 Sep 2002 23:41:23 GMT

Stephen Harding writes:

>> A "rotary" in the context of this discussion describes a non-piston
>> based IC motor that defines its combustion chambers by the rotation
>> of a single impeller (e.g. Wankel design).

> Nope, different!

> Radial simply refers to the fact that the cylinders are arranged
> radially around a central crankshaft.  Thus the Clerget (and Gnome)
> engines of some WWI aircraft are radials, as are the big Pratt &
> Whitney twin wasps, and others of some WWII US aircraft.  Both
> versions are air cooled.

Why go to war planes?  Airliners had radial engines until they were
replaced by jet and turbo-props engines, and finally fan-jets.

> However the "rotary" engine that Guy is referring to is different in
> that the crankshaft is stationary, and the cylinders rotate about
> the crank, unlike the P&W radials that had stationary cylinders that
> rotated a crank.

That is a rotating engine.  Rotary, engine design, means the
"piston(s)" rotate rather than reciprocate.  In this pursuit, Engines
were built with a toroidal cylinder housing containing two pairs of
curved pistons chased each other around with their support arms acting
like shears that brought then closer together and farther apart at
suitable times for intake, compression, expansion, and exhaust.  Wankel
went a step farther with an unconventional rotor similar to a vane
pump and by shaping the chamber of rotation, achieved the four strokes
of an internal combustion engine.

The flaw in rotary engines is thermodynamic, because the four strokes
always take place in the same but separate four locations of the
chamber, so that intake (freezing), compression, combustion (5000F),
exhaust, are a steady state thermal load.  Finding materials and
lubricants that can wipe past these extreme temperatures is beyond
today's technology, both from an expansion and friction aspect, and
probably will remain so.  To make rotary internal combustion engines
work, lower compression and rich mixtures are used, making them non
economical both in fuel and duration.

Reciprocating piston engines perform all four strokes in the same
place so that both piston AND cylinder see an oscillating operating
temperature in which a boundary layer and expansion cooling make the
apparent temperature so low that cast aluminum and cast iron can
contained them, less expensive materials and higher thermodynamic
performance.  It is not without reason that the Wankel did not
succeed.  Its flaws were known more than 80 years ago but the unusual
configuration had many wondering whether a rotary engine might be
possible after all.

> The Sopwith Camel and some other WWI aircraft had "rotary" engines.

Rotating engine.

Jobst Brandt  <jobst.brandt@stanfordalumni.org>  Palo Alto CA

From: jobst.brandt@stanfordalumni.org
Subject: Re: Revolutionary New Bicycle
Newsgroups: rec.bicycles.misc,rec.bicycles.racing,rec.bicycles.soc
Message-ID: <1hVd9.19135$Ik.471866@typhoon.sonic.net>
Date: Fri, 06 Sep 2002 03:27:57 GMT

Brad Anders writes:

>> The flaw in rotary engines, in contrast to reciprocating engines,
>> is thermodynamic, because the four strokes always take place in the
>> same but separate four locations of the chamber, so that intake
>> (freezing), compression, combustion (5000F), exhaust, are a steady
>> state thermal load.  Finding materials and lubricants that can wipe
>> past these extreme temperatures is beyond today's technology, both
>> from an expansion and friction aspect, and probably will remain so.
>> To make rotary internal combustion engines work, lower compression
>> and rich mixtures are used, making them non economical both in fuel
>> and duration.

> What killed the first generation Mazda Wankel motors was emissions,
> not cost, fuel economy, maintenance, or reliability.  The larger
> combustion chamber area per unit displacement of the Wankel motor
> causes high HC emissions that could not be sufficiently reduced by
> catalytic conversion.  The intake/exhaust overlap also contributed
> to poor CO and NOx emissions.

That sounds a lot like the defense of air cooled engines which are
close to the same thermodynamic problems but for different reasons.
All these years Porsche defended air cooling with the same promotional
arguments that were in fact wishful thinking.  Although the engines
could meet emission standards, they were far more expensive to build
and maintain and had poorer performance in power and durability than
equivalent water cooled engines.  It is for these reasons that the
concept was finally dumped.

> As for the thermodynamic and materials problems you describe, they
> are all real but have been sufficiently addressed to produce motors
> that have similar maintenance and reliability as standard IC engines
> today, judging from engine reliability and maintenance history of
> the 1995-generation RX-7 twin turbo.  Mazda is preparing to
> re-introduce Wankel engines to the US market in the 2003 RX-8,
> details of the engine design are here:

I am certain that the drawbacks that I listed, that were understood
many years ago will remain the hurdle they always were and can only be
ameliorated at greater expense, leaving the Wankel out of contention
for production cars.

> http://www.edmunds.com/future/2003/mazda/rx8/4drcoupe/preview.html

> The newer design has decent fuel economy, when compared to engines of
> similar output.

We'll have to wait and see.

Jobst Brandt  <jobst.brandt@stanfordalumni.org>  Palo Alto CA

From: jobst.brandt@stanfordalumni.org
Subject: Re: Revolutionary New Bicycle
Newsgroups: alt.religion.unification,alt.inventors,rec.bicycles.misc,
	rec.bicycles.racing,rec.bicycles.soc
Message-ID: <Uode9.19484$Ik.481322@typhoon.sonic.net>
Date: Sat, 07 Sep 2002 02:21:40 GMT

anonymous writes:

>>> Zoot, you be wrong.  The WWI rotary aero engines were rotary
>>> engines, in every meaningful sense.  The crankshaft stayed still
>>> and the engine went round.  That's as rotary as it needs to be.

>> To aircraft buffs, this may be the jargon but they are
>> reciprocating piston engines regardless of frame of reference.  It
>> was an erroneous design that believed more air cooling would be
>> achieved by moving the cylinders through the air.  As much as 27
>> cylinder (three tier 9 cylinder sets were used effectively with
>> stationary radial engines.

>> Radial engines always have an odd number of cylinders with one
>> master connecting rod to which the remainder are attached.

> Was it really erroneous? The WW1 biplanes with "rotary" radial
> engines typically had forward airspeed in the 80 to 100mph range,
> coupled with lubricants which were less than happy with high
> operating temperature, low oil pressure, and primitive combustion
> chamber/valve/port designs. I guess they needed all the cooling they
> could get. The rotating cylinder would have mad a fairly effective
> centrifugal impeller. AFAIK, they also frequently relied on total
> loss lubrication with no oil pump (beyond a low pressure injector
> pump to feed oil into the crankcase), so the top end lubrication was
> also driven by the same centifuge effect.

That's a fine defense of erroneous engineering but it doesn't hold
"air" so to speak.  If all these claims were true, then four and six
cylinder boxer engines of Continental and Lycoming do not work... but
they do and admirably, even though their cylinders are one behind the
other with respect to flight wind.

> The double and triple row "stationary" radials would have forward
> airspeed in the 300 to 400mph range when running at full power,
> together with 3 decades of advances in lubrication and engine
> design. They also had the benefit of operating at higher (colder)
> altitudes; late designs had fairly small cooling air intakes between
> the propeller hub and the cowling, with annular adjustable flaps for
> cooling air outlet to modulate the airflow through the engine
> enclosure to prevent overcooling in cold/high part throttle
> conditions.

Your arguments remind me of those of supporters of Mallet compound
articulated steam locomotives at the beginning of the 20th century.
In theory they were far superior to single stage articulated engines
and US steam engine builders went gaga over the concept.  Just the
same it went away shortly after introduction somewhat like rotating
aircraft and air cooled automobile engines.  The air cooled engine was
kept alive at Porsche where novelty was a sales point but even they
realized the time had come to drop the gimmick that served no purpose
while reducing power.

Jobst Brandt  <jobst.brandt@stanfordalumni.org>  Palo Alto CA

From: jobst.brandt@stanfordalumni.org
Subject: Re: Revolutionary New Bicycle
Newsgroups: alt.religion.unification,alt.inventors,rec.bicycles.misc,
	rec.bicycles.racing,rec.bicycles.soc
Message-ID: <sFue9.19864$Ik.490841@typhoon.sonic.net>
Date: Sat, 07 Sep 2002 21:59:52 GMT

anonymous writes:

> I wasn't, as far as I know, defending erroneous engineering. There
> were reasons why early aero engines had rotating cylinder blocks,
> just as there are sound engineering reasons why they were superseded
> by radial engines, and equally sound engineering reasons
> (engineering in the wide sense, including through life cost and end
> user convenience) for the long running success of the air cooled
> Lycoming engines.

Non-rotation radial engines preceded the engines you defend and
succeeded them for many years of reliable service.  I don't recall that
the rotation engine was used by commercial airlines but they did not
remain in general service after their military stint.  Many devices
are used in military applications that have little merit otherwise.  I
believe the rotating engine was one of these and was similar to the
Mallet locomotives to which I referred.  Just because many were built,
their short lives speak for themselves.

I recall the defense of air cooled automobile engines with similar
arguments that held no water.  The reason for air cooled engines in
automobiles was entirely emotional and a response to having no reliable
water pump seal.  In fact, WWII solved the boiling engine problem with
the carbon water pump seal that we use today with great reliability.
The Volkswagen beetle lasted as long as it did mainly through Mr
Nordhoff's religious belief in anything to do with Ferdinand Porsche.
Actually, the VW came from Czechoslovakia and was superficially
redesigned to be a "new" concept.  Upon Nordhoff's death, Mr Fiala
saved the VW company from imminent doom by scrapping the last beetle
and introducing the water cooled front engine Golf.

> Engineers devise solutions to the problems of their time, but they
> can't solve all of the problems.  Doubtless if the engineers
> designing the Clerget and Gnome/Rhone engines had had access to
> today's high performance materials, high performance lubricants,
> high quality fuels, computerised design and manufacturing processes
> and advanced understanding of internal combustion thermodynamics,
> they wouldn't have come up with an air cooled rotating radial with
> total loss lubrication and a pushrod operated single overhead
> valve.  The fact that thousands of units of the Clerget and
> Gnome/Rhone type saw successful frontline military service suggests
> that, within the constraints of the time, they were the best
> available engineering solution to providing 80 to 160hp from a
> light, cheap, robust powerplant.

Engineers (their engineering managers) are often wrong and pig headed
to the extent that they push their idea trough in spite of major flaws
in their concept.  The air cooled rear engine car is one of these as
was the Mallet steam engine.  There are many more.  Just because it
was built and on the market does not mean it was good or better than
others in that field.

Jobst Brandt  <jobst.brandt@stanfordalumni.org>  Palo Alto CA